A dejected-looking Yanukovych told reporters that "if there is a defeat, there will be a strong opposition." But he did not concede defeat, saying "I am ready to lead the state," and hinted he would challenge the results in the courts.

Some 12,000 foreign observers watched Sunday's unprecedented third round, which was ordered by the Supreme Court following the annulment of a fraud-marred November 21 runoff. The disputed outcome sparked massive protests inside the nation and a volley of recriminations between Russia and the West.

All three exit polls showed Yushchenko with at least a 15-percentage-point lead.

The state-funded Ukrainian Institute of Social Research and Social Monitoring Center showed Yushchenko with 58.1 percent of the vote and Yanukovych garnering 38.4 percent. The margin of error was plus or minus 2 percentage points.

The Western-funded Razumkov Center of Political Studies and Kiev International Institute of Sociology showed Yushchenko with 56.5 percent and Yanukovych collecting 41.3 percent. No margin of error was given.

A third exit poll, by Frank Luntz, a pollster for the U.S. Republican Party, and Douglas Schoen, of the Washington-based market research company Penn, Schoen & Berland, showed Yushchenko with 56 to Yanukovych's 41 percent, Schoen said. The margin of error was plus or minus 2 percentage points.

"Today Ukraine will have a new president -- Yushchenko. Everybody will feel the changes," Yulia Tymoshenko, a radical opposition leader and Yushchenko ally, told Ukraine's pro-opposition TV5.

Tymoshenko's calls for massive protests following the November 21 runoff earned her the nickname "Goddess of the Revolution." She appeared to revel in her role Sunday, wearing an orange-and-black shirt with the word "Revolution" running up the sleeves.

The Central Election Commission estimated that Sunday's turnout was around 75 percent.

The election outcome is momentous for Ukraine, a nation of 48 million people caught between the eastward-expanding European Union and NATO, and an increasingly assertive Russia, its former imperial and Soviet-era master.

Yushchenko, a former Central Bank chief and prime minister, wants to bring Ukraine closer to the West and advance economic and political reform. The Kremlin-backed Yanukovych emphasizes tightening the Slavic country's ties with Russia as a means of maintaining stability.

Yushchenko has promised to uproot the corruption that concentrated the former Soviet republic's wealth in the hands of about a dozen tycoons. Yanukovych has promised to continue work to boost Ukraine's economy -- which enjoys the fastest growth in Europe -- and pledged an increase in wages and pensions.

Serhiy Shetchkov, a 53-year-old Kiev voter, said he had cast his ballot for Yushchenko -- "of course."

"He is an economist and that's what the country needs right now," he said after slipping his ballot into a transparent box at Kiev's Music Conservatory. "I'm not as interested in all this talk about the European Union versus Russia. I'm interested in someone who can raise the standard of living, raise pensions, create more jobs."

The political crisis has cast a harsh spotlight on the rift between Ukraine's Russian-speaking, heavily industrial east and cosmopolitan Kiev and the west, where Ukrainian nationalism runs deep. Yanukovych backers fear discrimination by the Ukrainian-speaking west, and some eastern regions briefly threatened to seek autonomy if Yushchenko won the presidency.

"I am voting for independence [of eastern Ukraine], an end to feeding those lazy westerners! My vote goes to Yanukovych," said Hrihoriy Reshetnyak, a 44-year-old miner who cast his ballot in the prime minister's eastern stronghold, Donetsk.

Yushchenko, whose face remains badly scarred from dioxin poisoning he blamed on Ukrainian authorities, has tried to build on the momentum of round-the-clock protests that echoed the spirit of the anti-Communist revolutions that swept other East European countries in 1989-90.

"What we did during the last 30 days was a tribute to our ancestors," Yushchenko told reporters after voting in Kiev's trade union building. "I know they are looking at us from heaven and they are applauding."

The political crisis sparked arguments between Russia, which had backed Yanukovych and insisted that the vote had been free and fair, and the West, which stubbornly held out for a new showdown between the two candidates. Each side accused the other of undue interference in Ukraine's affairs.

Outgoing President Leonid Kuchma said he hoped the results would stick. "In my opinion, the one who loses should call and congratulate the winner ... and put an end to this prolonged election campaign."

Pollsters said they heard the same sentiment of fatigue from voters.

"I think the public is looking for this to be over," said Schoen, the American pollster.

Despite the huge presence of foreign observers, both campaigns complained of some violations. Yanukovych's campaign alleged that Yushchenko campaign material was found near some voting booths. Yushchenko's headquarters, meanwhile, complained that the names of dead people were included on a voter list in Donetsk.

Several thousand noisy revelers gathered in front of a stage on Independence Square. A giant banner hung nearby, reading "Tak" or "Yes" -- a Yushchenko campaign slogan. A Kiev brewery sold beer from an orange tent set up on the square.

Taras Korolyov, 28, brought his wife, Lesya, 25, and three-year-old daughter Olena to the square dressed in orange ski suits to celebrate a victory they described as "100 percent certain."

"We brought our daughter here to see the birth of freedom," Korolyov said as his daughter waved a tiny orange flag -- the opposition campaign's color -- and chanted "Yu-shchen-ko, Yu-shchen-ko."

A World War II-vintage motorcycle draped in orange ribbons drove through the crowd, honking.

"This bike saw the liberation of Kiev [from Nazi Germany], and now is seeing another liberation of Ukraine," said Oleksandr, the biker, who gave only his first name.

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